JP2002053964A - Head for vaporizing various precursors in chemical vapor phase deposition, and allowing the precursors to flow on semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vaporizer head for allowing the vaporized precursor compound for depositing a metal and other layers on a semiconductor to uniformly flow to a treatment chamber under a low pressure. SOLUTION: This vaporizer head has a valve-like body having the axis 20, a long cavity 22 and an input end and an output end. The cavity 22 has an opening 24 for receiving the flow of the precursor compound 46. A plurality of passages 30 and 34 for the flow of the vapor phase through the head 12 are provided. The passages 30 and 34 are extended in a radial direction around a wheel in a spoke shape along the cavity at angles 60, 62 and 64 inclined to the axis from the cavity 22 to a tapered output surface 32 of the head 12. The cavity 22 has a well-shaped bottom part 26 which traps liquid droplets or particles of the precursor compound, and prevents the liquid droplets or the particles other than the vapor phase from being separated away from the head. A plurality of passages have a sufficiently large diameter so that only the low pressure drop is present in the vapor phase flowing through the head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the vaporization of solid and / or fluid precursor compounds for depositing thin films of materials such as tantalum, tantalum nitride, titanium and the like.
And a head for injecting them as a gas phase into a processing chamber during chemical vapor deposition on semiconductor surfaces.

[0002]

BACKGROUND OF THE INVENTION Increased use and utility of semiconductors is driven by the development of new processes and materials for semiconductor design and manufacture, along with new or improved manufacturing equipment and hardware. Recent significant improvements in design and new materials have led to higher speeds and higher densities of VLSI operation. For example, the use of new materials, such as tantalum, titanium and other materials, has led to the need for more efficient methods of applying them to semiconductor surfaces.

[0003] Layers or films of metals such as tantalum, titanium, and the like can be deposited by CVD on exposed surfaces of semiconductor wafers during VLSI processing. For example,
Metal tantalum, that is, pentadiethylamino tantalum
The precursor compound (raw material compound) of (pentadiethylaminotantalum: PDEAT) is vaporized under certain conditions of pressure and temperature to obtain a gaseous phase and a gaseous phase of the compound used in the CVD process to form a metal layer. Precursors of various metals require low pressures (eg, 1 Torr or less and elevated temperatures (eg, about 100 ° C.)) to convert them into the gas phase and retain them . This will be described in detail below.

It is desirable that the metal layer deposited on a semiconductor wafer by CVD has a uniform thickness. To achieve this, the chemical vapor precursor of the metal flowing into the processing chamber in which the semiconductor wafer is processed is such that the direction and magnitude of the flow is such that the gas phase is evenly distributed toward the wafer and flows uniformly Need to be controlled as follows. Furthermore, CVs using precursor compounds of metals such as tantalum, titanium, etc.
Since the D process step is performed in a chamber maintained at a low pressure, the flow of gaseous gas into the chamber through the vaporizer head must be as disturbed as possible by the head. The head must have high flow conductance such that the pressure drop across the head is low (eg, a fraction of a Torr). Also, the temperature of the gas phase must be controlled as it passes through the head and enters the chamber to avoid condensation of the gas phase into droplets or particles. The present invention provides a simple and efficient vaporizer head with improved properties to meet these needs.

[0005]

SUMMARY OF THE INVENTION According to a specific embodiment of the present invention,
A vapor phase, low pressure vaporizer head of a precursor compound useful for chemical vapor deposition of materials such as titanium, tantalum, etc. on semiconductor surfaces is provided. This vaporizer head is
A body having a central axis, an outer diameter, an outer surface, an input end, an output end, and a length between the ends. This body is
A cavity is defined from the input end to near the output end for receiving a flow of vaporized precursor compound, but along a central axis that does not pass through the output end. The cavity has a closed well end for containing any condensed precursor compound droplets or particles that may be generated. The body also defines a plurality of passages through the head for flow of the gaseous phase out of the cavity through the outer surface. Each passage has a length and diameter and extends radially from the central axis at a respective angle to the central axis. The passages have sufficiently large diameters that only low pressure droplets flow through them, vaporize, and flow through the head so that the gas phase flows uniformly to the semiconductor surface. Disperse. The head provides the desired operating temperature for the gas phase flowing therethrough.

[0006] In one particular embodiment, the present invention is a vaporizer head for providing a semiconductor with a vapor phase of a precursor compound useful for chemical vapor deposition of a layer of material. The head has a body having a central axis, an outer diameter, an outer surface, an input end, an output end, and a length between the ends. The body defines a cavity from the input end to near the output end for receiving a flow of vaporized precursor compound, but along a central axis that does not pass through the output end. This cavity has a closed well-shaped bottom for containing any condensed precursor compound droplets or particles that may be generated. The body defines a plurality of passages through the head for flow of the gaseous phase out of the cavity through the outer surface. Each passage has a length and diameter and extends radially from the central axis at a respective angle to the central axis. The plurality of passages have a sufficiently large diameter and have a diameter
Only droplets with a pressure below Torr flow through them,
Vaporization disperses the gas phase flowing through the head such that the gas phase flows uniformly to the semiconductor surface. The head provides the desired operating temperature for the gas phase flowing therethrough.

In another specific embodiment, the present invention is a vaporizer head for flowing precursor compounds vaporized during chemical vapor deposition of metal and other layers onto a semiconductor to a processing chamber. The head has a body having a central axis, an inwardly tapered outer surface, an input end, an output end, and a length between the ends. The body defines a cavity along the central axis and having an opening at an input end for receiving a flow of vaporized precursor compound.
This cavity has a closed well-shaped bottom near the output end for containing droplets or particles of the precursor compound and preventing them from leaving the head except in the gas phase. The body defines a first plurality of passages for a gas phase flow. Each passageway has a length and diameter and extends radially from the cavity like a wheel spoke at a second oblique angle from the cavity to the lower outer surface with respect to the central axis. The body has a length and diameter, respectively, and defines a third plurality of passages extending slightly above the well bottom of the cavity to an output end of the body. The plurality of passages have a sufficiently large diameter to produce a gas phase flow therethrough during operation which is only a fraction of a Torr drop in pressure.

[0008] In yet another embodiment, the invention is an apparatus for chemical vapor deposition on a semiconductor wafer. The apparatus includes a processing chamber maintained at sub-atmospheric pressure, a platform or susceptor in the chamber for holding the wafer during processing, and for chemical vapor deposition of metal and other layers on the wafer. It has a vaporizer head for flowing the vaporized precursor compound into the chamber and onto the wafer. The head has a body having a central axis, an outer surface, an input end, an output end, and a length between the ends. The body defines a cavity extending along a central axis having an opening at an input end for receiving a flow of vaporized material. The cavity has a bottom end on a closed well near the output end of the body to collect droplets and particles of the precursor compound and prevent them from leaving the head except in the gas phase. The body defines a plurality of passages through the head for a flow of vaporized material. Each passage has a length and diameter and extends radially from the cavity to the outer surface, along the cavity, at an angle to the central axis, and around the cavity, like a spoke of a wheel. The passages have sufficiently large diameters to provide a pressure drop of a fraction of a Torr to the vaporized precursor flowing therethrough so that the vaporized precursor is uniformly distributed over the wafer surface. Disperse the flow through the head as it flows.

With a full appreciation of the many advantages of the present invention,
A better understanding of the present invention may be had from the following description, given in conjunction with the accompanying drawings and claims.

[0010]

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, chemical vapor deposition (CV) of various materials according to the present invention on a semiconductor.
An apparatus 10 useful in D) is shown. Apparatus 10 includes features of the present invention and is disposed on a platform below processing chamber 14, shown in cross-section, (shown by a dotted rectangle), susceptor (platform) 16, and head 12. Semiconductor wafer 18. Chamber 14 is adapted to be maintained at sub-atmospheric pressure during CVD processing of wafer 18. During this process, the wafer is heated to an elevated temperature (eg, about 400 ° C.) by platform 16. Chamber 14 and platform 16 are well known and will not be described further here.

The carburetor head 12 is hermetically sealed to the top of the chamber 14 by means not shown. The body of the vaporizer head 12 is generally cylindrical,
It has a vertical central axis 20 aligned with the center of the wafer 18. The head 12 has a vertical cavity 22 that is concentric with the axis 20. This cavity has a top opening 24 for entry of the gas phase and a bottom end 26 on a closed well. A plurality of elongated passages 30 radiate outwardly and angularly downwardly from the cavity 22 in the shape of wheels. As will be described below, each passage 30 is vertically spaced and uniformly spaced circumferentially about central axis 20. Each passage 3
0 denotes the input end opening to the cavity 22 and the head 1
Processing chamber 14 through two tapered sides 32
To the output end. Also near the bottom end 26 of the cavity 22 is a group of small passages 34 that radiate outward and downward. Each of the passages 34 has an input end opening in the cavity 22 and an exit opening into the chamber 14 through the flat bottom surface 36 of the head 12, located somewhat above the bottom end 26.

During operation of the apparatus 10, the vaporizer head 12
The desired temperature (eg, about 100 ° C.) is raised by an electric heater 40 of a commercially available type. A precursor source (not shown), as indicated by arrow 42,
The precursor is supplied to module 44. The module is
Ultrasound and / or thermal energy can also be applied to the incoming precursor, if desired, so that the precursor properly vaporizes as the gas phase enters the input opening 24 of the head 12, as indicated by arrow 46. To be done. This vaporized substance, as indicated by the arrow,
It flows below the cavity 22, into each of the passages 30 and 34, and into the process chamber 14. As described in more detail below, the vaporizer head 12 includes a passage 30
And 34 flow uniformly into the chamber and downwardly toward the surface of the wafer 18. Passage 3
The gas phase stream flowing through 0 and 34 is maintained at the desired temperature by heat transferred from the vaporizer head 12 formed of a solid block of aluminum having good thermal conductivity. Cavity 22 and respective passages 30, 34
Is easily processed into the main body of the head 12.

The well-shaped end 26 at the bottom of the remaining cavity 22 serves to collect any droplets or particles that happen to be present in the gaseous stream 46 entering the input opening 24 of the cavity 22. The suspended liquid or solid material collected at the well end 26 is quickly vaporized by heat from the head 12 and thus is prevented from entering the chamber except for the gas phase.

Referring to FIG. 2, a perspective view of the carburetor head 12 is shown. The exit end of passage 30 is shown arranged in three vertically spaced circular rows, indicated by respective brackets (curly braces) 50,52,54. Passage 3 in each of rows 50, 52, 54
Zeros are spaced at the same angle relative to the central axis 20. In the particular example of the carburetor head 12 shown, the passages 30 are equally spaced by a 45 ° angle about the central axis of the body 12. Therefore, rows 50, 5
There are 8 passages in each of 2, 54, for a total of 24 passages. The small passages 34 are spaced by a 90 degree angle,
There are four, and there are a total of 28 passages when passages 30 and 34 are combined.

Referring to FIG. 3A, dotted line 3A-3 in FIG.
A cross-sectional view of the carburetor head 12 along A is shown.
Although shown small, it should be noted that this cross section of head 12 is the same as that shown in FIG. As shown in FIG. 3A, the top row 50
Are visible in this cross-section, each having an inlet end 30-1 opening just below the upper opening 24. These passages 30 (and other passages 30 in this figure) are formed in the body of the head 12 at an angle indicated by the arc 60 with respect to the central axis. The other two passages 30 in the top row 50 have a central axis 2 with respect to the passages shown.
Although not visible in FIG. 3A since it is located at an angle of 90 degrees around zero, it has a respective input end 30-1 opening near its upper opening 24. These invisible passages also exist at the same downward angle 60.

As previously described with respect to FIG. 2, in the particular embodiment of the invention illustrated herein, the carburetor head 12 includes eight passages 30 having a lower outlet end in an upper row 50. And all of their outlet ends lie along a single circle around the tapered surface 32 of the head 12. As just described, only four of these passages 30 have openings at input end 30-1 at 90 degree intervals near upper opening 24.

Referring to FIG. 3B, a step diagram of the head 12 is shown along the line 3B-3B in FIG. FIG. 3B
It is rotated by 45 degrees with respect to FIG. 3A. As shown in FIG. 3B, the passage 30 (two visible) in the upper row 50 has an input end 30-1 under the aperture (FIG. 3A).
Having a 0-2, passage 30 is formed in the body of head 12 at an angle indicated by arc 62. This angle is
The input end 30-2 aperture is somewhat larger than the angle 60 so that it is below the input end 30-1 aperture. The other two passages 30
Has two passages 30 visible in the top row 50
3B, which is not visible in FIG. 3B, but has an end 30-2 opening in the cavity 22. By making the angle 60 in FIG. 3A slightly different from the angle in FIG. 3B, the input ends 30-1, 30-2, 30-3, 30-4, and 30 of each of the 24 passages 30 are provided.
-6 are interspersed downward along cavity 22 at an interval about axis 20. Thereby, the gas phase flowing to the cavity 22 is efficiently dispersed. Four small passages 34
(Only two of them are visible in FIG. 3A) are formed at an angle indicated by the arc 64 such that the top end 34-1 of each of the passages 34 is a small distance above the well bottom end 26 of the cavity 22. Is done.

Referring to FIG. 4, there is shown a graph 70 illustrating the relationship between the gas phase and the solid phase (or liquid phase) of a CVD precursor compound as a function of temperature versus pressure. The horizontal axis of the graph 70 indicates the temperature in degrees Celsius, and the vertical axis (non-linear) indicates the pressure (Torr). The graph 70 shows, for example, tetradimethylaminotitanium (TDMA).
The precursor such as T) has a first line 72 in the gas phase. As the temperature moves sufficiently to the left or the pressure moves away from line 72 and above graph 70, the material returns to the solid (or liquid) state. If a given precursor (eg, TDMAT) was used for CVD, line 7
It is convenient to use the operating value of temperature and the operating value of pressure as shown at point 73 on 2 above. In the case of TDMAT, point 73
Is about 50 ° C. and the pressure is about 0.5 Torr.
Graph 70 shows a second precursor, pentaethylmethylaminotantalu.
m: PEMAT) has a second line 74 indicating the gas phase relationship and a point 75 indicating the operating value of temperature and pressure. Similarly, graph 70 shows pentadiethylamino tantalum (pe
It has a line 76 and operating point 77 for ntadiethylaminotantalum (PDEAT) and a line 78 and operating point 79 for pentadimethylaminotantalum (PDMAT).

The various precursor compounds shown are for the device 10
It is evident from graph 70 that each of them requires low chamber pressure when used in CVD processes. At normal ambient temperatures and pressures, these materials are solid (or liquid), but at suitably low pressures and elevated temperatures, it is possible to change the phase to the gaseous phase. As indicated by arrows 46, these materials are delivered to vaporization head 12 (see FIG. 1).
Therefore, it is necessary that the flow of the gaseous phase is not significantly obstructed so that the gaseous phase does not return to the solid phase (or liquid phase) when passing through the head 12. Accordingly, the head 12 must have high-flow-conductance (high flow conductance), ie, a small pressure drop across the head (eg, a fraction of a Torr). Also, head 12 should maintain the gas phase at a desired operating temperature (eg, point 73 on line 72 of graph 70) as it passes through head 12. The head 12 is easily maintained at a desired temperature by the heater 40.

In the particular embodiment of the invention shown here, the vaporizer head 12 is somewhat valve shaped. The diameter of the large passage 30 through the head is about 0.2 inches (about 0.508 cm), and the diameter of the small passage is about 0.1 inches (about 0.254 cm). The lengths of passages 30 and 34 are much longer than their respective diameters. The passages 30 and 34 through the head 12 are relatively large, so that the plasma excitation gas can pass through the head 12. This makes it possible to place a plasma excitation source on the inlet 24 of the head 12 and on the outside of the chamber. The diameter of the cavity 22 is about 0.5 inches (about 1.
77 cm) and the cavity is at the bottom 3 of the head 12.
6, extending downward along axis 20 to near (but not through the head). The diameter of the upper part of the head 12 is about 3
Inches (approximately 7.62 cm), and the lower part of the head is
About 1.5 inches (about 3.81 cm) at the bottom surface 36
The diameter is inclined. The length of the head from the top entrance 24 to the bottom 36 is about 4 inches (about 10.16 cm).
It is. Angle 60 (FIG. 3A) is about 28 degrees, angle 64 is slightly larger, and angle 62 (FIG. 3B) is about 35 degrees.
Degrees. During the CVD process, at pressures of 1 Torr or less (see FIG. 4), a flow of about 2 to 10 sccm of a vaporized precursor (eg, TDMAT) mixed with about 100 to 200 sccm of argon is headed into chamber 14 ( (Maintained at the desired temperature). The temperature of the wafer was about 400 ° C. and was placed about 0.5 inch (about 1.77 cm) from the bottom 36 of the head 12.
The processing cycle lasted several minutes.

The above description is illustrative, but not limiting. Various modifications and alterations of the carburetor head 12 utilizing features of the present invention are possible by those skilled in the art and can be made without departing from the spirit or scope of the invention as described and defined by the claims. . For example, the invention is not limited to the use of only the described precursors, but is useful with other CVD precursors. Further, the invention is limited to the particular set of vaporizer head sizes, diameters, or particular numbers, sizes and angles of passages 30 and 34, or the particular materials or methods of manufacture of the vaporized heads described above. Not done.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a vaporizer head including features of the present invention, as well as a portion of an apparatus for chemical vapor deposition of a substance on a semiconductor wafer.

FIG. 2 is a perspective view of a vaporizer head showing the arrangement of various gaseous passages through each opening and head.

3A is obtained by 3A-3A shown in FIG. 2;
FIG. 3 is a cross-sectional view of a vaporizer head showing a relationship between a size and an angle of a gas phase passage passing through the head.

3B obtained by 3B-3B shown in FIG. 2;
FIG. 3 is a cross-sectional view of a vaporizer head showing a relationship between a size and an angle of a gas phase passage passing through the head.

FIG. 4 is a graph showing the relationship of the vapor relative solid phase (or liquid phase) of various CVD precursor compounds as a function of pressure and temperature.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Minshi United States of America California 94306 Palo Alto Chasir Avenue 151 (72) Inventor Xiaozion Yuan United States of America California 95014 Cupertino Rainbow Drive # 3 7374 (72) Inventor Unzone Chan United States of America CA 95129 San Jose Rundleswood Court 5847 (72) Inventor Ann N. Guen United States 95035 Milpitas Columbus Drive 1075 F-term (reference) 4K030 AA11 BA17 BA18 CA04 EA01 FA10 KA45 LA15 5F045 AF01 BB02 DP03 EC09 EE02 EF01 EF01EF

Claims (15)

[Claims] 1. A vaporizer head for providing a vapor phase of a precursor compound useful for chemical vapor deposition of a material layer on a semiconductor, comprising: a central axis, an outer diameter, an outer surface, an input end, an output end, and A body having a length between the input end and the output end, the body defining a cavity along the central axis from the input end, not penetrating, near the output end for receiving a flow of vaporized precursor compound; Wherein the cavity has a bottom on a closed well for containing droplets or particles of condensed precursor compound that may form, and wherein the body is out of the cavity through an outer surface. Defining a plurality of passages through the head for the flow of the gas phase,
Each of the passages has a length and a diameter, extends radially from the central axis at a respective angle with respect to the central axis, and the plurality of passages provide about 1 Torr to a gas phase flowing therethrough. The head has a diameter large enough to provide a dispersion of the gaseous phase flowing through the head so as to cause a small pressure drop and so that the gaseous phase flows uniformly over the semiconductor surface; Providing a desired operating temperature to the gas phase flowing through the head. 2. There is a first plurality of passages and a second plurality of passages, wherein the first plurality of passages have respective lengths substantially greater than the length and diameter of the second plurality of passages. The carburetor head according to claim 1, wherein the carburetor head has a diameter and is provided at a different angle from the inclined angle of the second plurality of passages with respect to the central axis. 3. The first group of passages has their output ends provided in at least one circular row located around the outer surface of the lower body, and the input end of the passages is 2. The carburetor head according to claim 1, wherein the carburetor head is provided around the central axis along the cavity. 4. The lower portion of the body has a tapered surface that slopes inwardly toward an output end, and is equally spaced around and along the tapered surface. 4. A carburetor head according to claim 3, wherein there are three circular rows and the output end of the passage is along each row. 5. The body of the head is somewhat spherical and some of the passages are at an oblique angle with respect to the central axis, where the other passages are at an oblique angle, and open to the cavity. The input ends of the passages are provided along and around the cavity in a desired pattern, respectively, and the flow of gas phase into the cavity is a semiconductor that is processed by chemical vapor deposition. 5. The carburetor head according to claim 4, wherein the carburetor head is efficiently distributed from the head and flows uniformly. 6. A vaporizer head for flowing vaporized precursor compounds to a processing chamber during chemical vapor deposition of metals and other layers on a semiconductor, the vaporizer head having a central axis and an internally tapered interior. A lower outer surface, an input end, an output end, a body having a length between the input end and the output end, wherein the body defines a cavity along the central axis and directs a flow of the vaporized precursor compound. An opening at an input end for receiving, the cavity having a bottom on a closed well near an output end for containing droplets and particles of the precursor compound, and excluding the gas phase from the head. Preventing the body from separating, wherein the body defines a first plurality of passages for a gas phase flow, each passage having a length and a diameter, from the cavity to the lower outer surface; Of the spokes of the wheel at a first oblique angle with respect to the central axis Extending radially from the cavity, the body defining a second plurality of passages for gaseous phase flow, each passage having a length and a diameter, from the cavity to a lower outer surface. Extends radially from the cavity like a spoke of a wheel at a second oblique angle with respect to the central axis, and the body has a length and diameter, and a distance from the well-like bottom of the cavity. Defining a third plurality of passages extending from above to an output end of the body;
A carburetor head, wherein the plurality of passages have a sufficiently large diameter to cause a pressure drop of a fraction of a Torr in the flow of the gas phase flowing therethrough during operation. 7. The method of claim 1, wherein the first and second plurality of passages are about 0.2.
Inch diameter, and the third plurality of passages is about 0.1
7. The carburetor head according to claim 6, having a diameter of inches, the length of the body is about 4 inches, and the diameter of the cavity is about 0.5 inches. 8. The first and second passages each have an output end spaced apart along a plurality of spaced circular rows disposed about a tapered lower outer surface of the body. 7. The carburetor head according to claim 6, wherein the input ends of the passages are arranged in a desired pattern around the central axis along a length of the cavity. 9. The first plurality of passages has twelve equally-spaced passages and the second plurality of passages has twelve equally-spaced passages, each having a diameter of about 0.2 inches; 9. The carburetor head according to claim 8, wherein the output ends of the passages are respectively provided along three circular rows. 10. The input ends of the plurality of third passages are respectively disposed in cavities above the well-shaped bottom,
9. A carburetor head according to claim 8, wherein the output ends are provided around the output end of the body. 11. The carburetor head according to claim 6, wherein said body is aluminum. 12. The vaporizer of claim 6, further comprising a heater disposed around an upper portion of the body to adjust a temperature of a gas phase flowing through the head during operation. Vessel head. 13. An apparatus for chemical vapor deposition on a semiconductor wafer, said apparatus being in a processing chamber maintained at sub-atmospheric pressure and in a chamber for holding a wafer during processing. A platform or susceptor; and a vaporizer head for flowing a vaporized precursor compound to the chamber and onto the wafer for chemical vapor deposition of metals and other films on the wafer; A shaft, an outer surface, an input end, an output end, a body having a length between the input end and the output end, the body having an opening at the input end for receiving a flow of vaporized material. Extending along the central axis having a cavity on a well closed near the output end of the body for collecting droplets and particles of the precursor compound so that they do not leave the head except in the gas phase. Bottom edge And the body defines a plurality of passages through the head for a flow of vaporized material, each passage having a length and a diameter,
And extending radially from the cavity to the outer surface, at an angle to the central axis, along and around the cavity, such as spokes of a wheel, wherein the plurality of passages are substantially With a large diameter, the vaporized precursor flowing therethrough is given a pressure drop of a fraction of a torr and the flow distribution through the head is such that the vaporized precursor flows evenly over the wafer surface. An apparatus characterized in that: 14. The apparatus of claim 14, further comprising a heater coupled to said vaporizer head such that as various precursor compounds flow through said head, they are maintained at a desired gas phase temperature. Item 14. The apparatus according to Item 13. 15. The heater of claim 1, wherein the heater is coupled to an upper outer portion of the carburetor head.
An apparatus according to claim 4.